Filtering medium and process of making same.



No. 737,116. V PATENTED AUG. 25, 1903.

E. M. KNIGHT. FILTERING MEDIUM AND PROCESS 0F MAKING SAME.

APPLICATION FILED MAY 23, 1903.

NQ MODEL.

UNITED STATES Patented August 25, 1903.

EDWARD. M. KNIGHT, OF BROOKLYN, NEW YORK.

l-'lLTl-:Rmel MEDIUM AND PR-oCI-:ssoF MAKING SAME.

SPECIFICATION forming part of Letters` Patent No. 737,116, dated August 25, 1903.

Application sled May 2s, 190s. serial No. 158,405. [No specimens.)

To @ZZ whom t may concern:

Be it known that I, EDWARD MARTIN KNIGHT, a citizen of the United States of America, residing at Brooklyn, New'York, have invented certain new and useful Improvements in Filtering Mediums andin the Process of Making the Same, of which the fol- Y lowing is a specification.

or film broken away. Fig. 2 is a cross-see.

tion view of the pad or disk.'

The filtering properties of asbestos-have long been understood and appreciated by those skilled in this art, and the rapidity with which pads, disks, or films of asbestos or asbestos and cotton bers commingled and compressed remove suspended. sedimentary matter from water and other liquids has comf mended this type of filter to the public. In many instances it has been desirable to cause y the water to be filtered to pass through a bed of granulated or pulverized purifying material, as bone-black or charcoal; but the dif-Y iculty heretofore has beento so combine such material `with asbestos that the carbon is retained and the fibers of theasbestos arenot disturbed or injured. If the carbon is placed between two layers or sheets of asbestos, the said sheets will not adhere, as the interposed carbon prevents the fibers of one sheet or layer from interlocking with those of the other sheet or layer. Therefore'the sheets are readily separated, and the result is an unsatisfactory iilter-bed liable to derangement.

in handling. In my practical experience with filters employing asbestosas a filtering-bed I have discovered that the carbon may be combined with the asbestos in such a man- 11er that two vseparate sheets of the asbestos may be so joined by the interlocking of the fibers that the interposed carbon is retained in Situ and the sheets rendered practically homogeneous.

In carrying out my invention I take the iibers of comminuted asbestos derived from a carding or other similar machinev and subject the same to pressure to form a thin uniform disk or pad a. To one of the surfaces of such pad I apply the carbon b, the form which I prefer to use being a paste made by mixing iinely-pulverized carbon with water and applying the same by means of a brush, although the carbon may be applied in a dry state without departing-from the spirit of my invention. I prefer not to coat the entire surface of the pad or disk, but to leave a sur.-

rounding edge or surface c uncoated, so that when a second and uncoated layer or pad d is placed on the ltop of the first-named layer or pad the exposed fibers of the one layer will interlock withvthe bers of the other layer when the two layers which comprise the completed disk or pad are subjected to pressure in a machine of suitable character..

To facilitate the unionof the separate sheets or layers which make up the complete disk or pad, (and I may use as many of such sheets or layers as found necessary or. desirable,) I prefer to form a slight depression e inthe sheet which is to carry the carbon, this depression including the whole or part of the surface to be coated, and in this depression Y,

I place the carbon. Then I apply the second layer and subject the combined layers to pressure, which unites them, as before eX- plained, and squeezes out any air that may be `contained between the layers. The result is a homogeneous disk or pad of comminuted asbestos with a concealed layer of carbon so protected that the disk maybe handled without danger of cracking or injuring the carbon surface. Such a pad is cheaply made, possesses the best of ltering and purifying properties, andgives most satisfactory results.

1. The process of making ltering disks or pads which consists in making a compressed layer or disk composed of fibers then applyving a lm of carbon to a portion` only of one side or surface of said layer or disk, s0 as to leave a surrounding exposed portion, and finally laying a second fibrous layer or disk upon the coated surface of the first-named layer or disk and subjecting the combined layers to pressure to cause the bers of one layer or disk to interlock with those of the other layer or disk and produce a homogeneous filter-pad.

i 2. The process of making filtering disks or pads which consists in subjecting comminuted asbestos or other fibers to pressure to form layers or disks, and forming one of said layers or disks With a depression inside of its outer edge; then applying a film or coating of carbon to the depressed portion of said layer or disk and nally placing upon the carbon-coated layer or disk a second and uncoated filtering layer or disk, and subjecting the combined layers or disks to pressure to drive out the air between them and to interlock the ibers of the uncoated layer or disk EDWARD M. KNIGHT.

Witnesses:

GEORGE HARRISON, HENRY W. LYNDEN. 

